Exam 1 Flashcards
(50 cards)
What are the main characteristics of life?
Living things are organized and maintained by energy flow and nutrient cycling, with cells as the functional unit. They acquire and use materials and energy, maintain homeostasis, respond to stimuli, grow, develop and reproduce, use DNA as genetic material, and have the capacity to evolve. Metabolism, the total of all life-sustaining chemical reactions, is also key.
What is binomial nomenclature?
Binomial nomenclature is a 2-part scientific naming system using the Genus name followed by a specific epithet, such as Homo sapiens or Canis lupus.
What is the scientific method?
The scientific method involves observation, forming a question, developing a hypothesis, making a prediction, performing an experiment, analyzing the results, and forming a conclusion. If the hypothesis is not supported, it should be revised.
What is the difference between a scientific theory and a scientific law?
A scientific theory is a hypothesis that has not been disproven after years of testing, is consistent with all evidence, and helps make successful predictions. A scientific law is a generalization about data that describes what to expect in a particular situation. Laws may have exceptions and can be modified or rejected based on new evidence.
What are the essential elements of life?
About 25 elements are essential to life, with carbon, hydrogen, oxygen, and nitrogen making up 96% of living matter. The remaining 4% consists of elements like calcium, phosphorus, potassium, and sulfur.
Describe the subatomic particles of an atom.
Atoms consist of neutrons (no charge), protons (positive charge), and electrons (negative charge). Neutrons and protons form the atomic nucleus, and electrons form a cloud around the nucleus.
What are valence electrons?
Valence electrons are those in the outermost electron shell of an atom, which largely determine its chemical behavior.
Describe the different types of chemical bonds.
Covalent bond: sharing of electron pairs.
Polar covalent bond: unequal sharing of electrons.
Ionic bond: transfer of electrons, resulting in ions.
Hydrogen bond: attraction between a hydrogen atom and an electronegative atom.
What are the unique properties of water?
Water is a biological medium, and is essential for all living organisms. It acts as a solvent for polar molecules. Water has cohesiveness due to hydrogen bonds, and has a high specific heat, and unusual density properties.
What are macromolecules and their four main classes?
Macromolecules are large molecules composed of thousands of covalently connected atoms. The four main classes are carbohydrates, proteins, nucleic acids, and lipids.
What are the functions of carbohydrates?
Carbohydrates include sugars and their polymers, serving as a major fuel for cells and as raw material for building molecules. Polysaccharides such as starch, glycogen, and cellulose have storage and structural roles.
What are the characteristics of lipids?
Lipids are a diverse group of hydrophobic molecules with little or no affinity for water. They include fats, phospholipids, and steroids.
What is the structure of a phospholipid?
A phospholipid has a hydrophilic head (phosphate group and its attachments) and two hydrophobic fatty acid tails. They form a bilayer in cell membranes.
What are the functions of proteins?
Proteins have many functions including structural support, storage, transport, cellular communication, movement, and defense against foreign substances. They are polymers of amino acids.
What is protein denaturation?
Denaturation is the loss of a protein’s native conformation due to changes in pH, salt concentration, temperature, or other environmental factors, making it biologically inactive.
What are nucleic acids?
Nucleic acids, like DNA and RNA, are the molecules of heredity. Other nucleotides act as intracellular messengers, energy carriers or coenzymes.
What are the main points of modern cell theory?
All living things are composed of one or more cells, the smallest living organisms are single cells, and all cells arise from existing cells. Cells contain hereditary material (DNA) that they pass down via cell division.
What are the common features of all cells?
All cells are enclosed by a plasma membrane and use DNA as hereditary blueprint. They contain cytoplasm, obtain energy and nutrients from their environment, and have many common structures and components.
Why are cells so small?
Cell size is limited by the ratio of surface area to volume. A smaller cell has a greater surface area relative to its volume.
What is the plasma membrane?
The plasma membrane is the boundary separating a living cell from its nonliving surroundings. It exhibits selective permeability, and is a fluid mosaic of lipids and proteins.
What are the two main types of cells?
The two main types of cells are prokaryotic (bacteria and archaea) and eukaryotic.
What are the main differences between prokaryotic and eukaryotic cells?
Prokaryotic cells lack a nucleus and other membrane-bound organelles. Eukaryotic cells have a membrane-bound nucleus and other organelles. Eukaryotic cells are also generally much larger than prokaryotic cells.
What are the functions of the nucleus?
The nucleus controls the cell’s metabolic functions and houses the cell’s DNA, which carries the body’s genetic code.
What are the functions of the endomembrane system?
The endomembrane system, including the endoplasmic reticulum (ER) and Golgi complex, compartmentalizes the cell, produces, stores, modifies, transports and digests macromolecules.
